Laboratory Measurement of the Actual Tire-Pavement Contact Pressure Using a Static Test Device

It is well-known that the tire-pavement contact pressure (TPCP) is hardly circular or uniformly distributed as often assumed. In this study, using a simple but effective static test set-up, numerous actual TPCPs between a loaded wheel-tire and the surface of an asphalt-mix slab were measured in the laboratory. Various TPCP loading conditions were investigated, including varying the tire inflation pressures, varying the load levels, and using different tire types, different tire tread patterns, and tire ages. Analysis of the results indicated that a linear proportional relationship existed between the following variables: (a) Tire inflation pressure and TPCP, (b) load level and the effective tire-pavement contact area, and (c) load level and TPCP. At a fixed constant tire inflation pressure, an increment in the load level significantly impacted the tire edges compared to the middle zone, and at a constant wheel loading, an increase in the tire inflation pressure will result in possibly a 1.5 times increase in the TPCP. This is detrimental to pavements and is undesirable. Furthermore, the TPCP under new tires was observed to be closer to being uniformly distributed than that under the old tires. In other words, in terms of distresses, if all other factors are equal, an old tire will likely cause more damage to an asphalt pavement than a new tire.